Obesity has reached epidemic proportions in the United States proving to be a very difficult health challenge for patients and physicians. More than two-thirds of adults are currently overweight or obese, putting them at increased risk for diabetes, heart and vascular disease, and cancer. These health issues frequently bring at- risk patients to their physicians who can be an effective resource for helping them manage their weight and treat obesity. Several prominent national organizations, including the US Preventive Services Task Force (USPSTF), now recommend that physicians screen and assess all adult patients for obesity and offer counseling intervention to promote weight loss. Provision of this service by physicians has recently become reimbursable, highlighting the significance of this public health epidemic. Physicians, however, have traditionally received little medical school education in weight management counseling (WMC). Therefore, the Association of American Medical Colleges has emphasized that WMC skills be incorporated into a medical school's curriculum while cautioning that any uncertainty regarding treatment of overweight and obesity not preclude physicians-in-training from learning these skills. To date, a comprehensive, integrated, and competency-based WMC curriculum for medical students has neither been developed nor does evaluated and medical student WMC training remain seriously limited. We propose to test the effect of such a curriculum across 10 medical schools on medical students' WMC knowledge, attitudes and skills. Using a group randomized controlled trial (RCT), we will compare a multi-modal curriculum intervention MS Weight (Medical Students learning WEIGHT management counseling skills) to traditional education (TE) on WMC skills among 3rd year medical students as measured by an Objective Structured Clinical Examination (OSCE) (primary outcome) and student self-report of WMC self-efficacy (secondary outcome). MS Weight is unique because it will be offered throughout the first three years of medical school and consist of a tested web-based curriculum, a series of interactive counseling practice opportunities with observation and feedback, video demonstrations, a formative web-based OSCE, and a school WMC social media Facebook page. Another key innovative component of MS Weight focuses on enhancing the 3rd year student clerkship experience (Family Medicine or Internal Medicine), in which WMC skills, modeling, and providing feedback are taught to clerkship directors and preceptors so that they can model and reinforce ideal WMC practices for their students. MS Weight is the first RCT to comprehensively incorporate the teaching of WMC skills into medical school curricula and compare it to standard current traditional education regarding WMC knowledge, attitudes and skill outcomes. This study is very timely given recent public health momentum strongly advocating for physician involvement in WMC and the recent dissemination of obesity treatment clinical guidelines. Medical schools are ideal venues for closing the gap between recommended physician behaviors and teaching physicians-in-training the WMC skill set needed to help reduce morbidity and mortality rates among people who are overweight or obese.